The two-dimensional and self-consistent fluid model of the SF6 discharge was established based on the electron and ions continuity transfer equations coupled to Poisson’s equation, and also simultaneously considered the photoionization event, and then the flux corrected transport technique (FCT) was employed to numerically solve the particle flux-continuity equations, and some significant microphenomena were achieved that the dynamic behaviors of the charged particles, the spatio-temporal evolution of the discharge channel and the transformation law of the avalanche-streamer for the SF6 narrow-gap were revealed in this paper.